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High oxides

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nkhanbham

Master

Posts: 53

Joined: Wed Feb 25, 2015 3:03 pm

Post Mon Dec 19, 2016 2:02 pm

High oxides

We have been having some issues on our Helios with passing the Tuning protocol due to high oxides (>0.03). Sometime this has been just the once and then upon repeating (Full Tuning protocol) the oxides are down and it passes. On two occasions, however, the Tuning has failed because of high oxides on consecutive occasions (three attempts in a row; range 0.0315-0.0383) followed by eventually passing also on consecutive attempts (range 0.0217-0.0247). No settings were changed in between Tuning runs. Has anyone experienced this and have an idea of cause(s)?
Thanks for feedback,
Naeem
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mleipold

Guru

Posts: 5796

Joined: Fri Nov 01, 2013 5:30 pm

Location: Stanford HIMC, CA, USA

Post Mon Dec 19, 2016 3:42 pm

Re: High oxides

Hi Naeem,

What have been your Makeup Gas and Nebulizer Gas values? Both when Tuning has passed, and when Tuning has *not* passed.

One of the more common reasons for an oxide-related Tuning failure is because of a seal problem: not tightening the screw cap on the Helios spray chamber sufficiently, a damaged o-ring in the spray chamber, slightly mis-aligned torch assembly, not getting a good "match" on the spray chamber-to-injector ball joint, etc.

In all these cases, room air leaks in. In many cases, sufficient air leaks in to prevent plasma ignition. In other cases, it just changes the MG value significantly and raises the Oxide level.


Mike

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